1. Field of the Invention
The present invention relates to a method for forming an interlayer insulation film in a semiconductor device, and more particularly to, a method for forming an interlayer insulation film in a semiconductor device by using a porous low dielectric insulation film including air having the lowest dielectric constant in the form of pores.
2. Discussion of Related Art
The ultimate objects of the semiconductor manufacturing technology are high integration and high performance of a semiconductor device. The most important factor for attaining the high integration and high performance is a copper wiring process. Because a copper line is rarely etched by a general etching material, an inlaying method for filling and planarizing copper after etching an interlayer insulation film has been used.
In addition, when low resistance characteristics of the copper line are not satisfactory, the copper line is combined with a low dielectric to reduce an RC delay, thereby manufacturing a high performance semiconductor device. A few kinds of materials have a low-dielectric constant. Recently, an organo silicate glass (OSG) has been generally developed. Here, silicon-oxygen-methane (or carbon) bonding partially exists in or coexists with silicon-oxygen bonding, to reduce the dielectric constant to 2.2 band. In case micro-pores are additionally formed in an interlayer insulation film, the dielectric constant can be more lowered. However, if porosity of the interlayer insulation film increases, pores are possibly coupled to form open pores. Such open pores form diffusion paths of metal ions, to facilitate metal diffusion. Moreover, when a high pressure is applied to the interlayer insulation film during a succeeding process for forming a metal barrier layer or a metal seed layer, the interlayer insulation film may be destroyed or collapsed. In addition, when the metal ions are diffused through the open pores, adjacent metal lines are shorted or leakage current is increased. As a result, electrical properties of the device are deteriorated or defects are generated.